From the birth of the devil in ancient Persia, where a beloved family dog becomes a seething beast, to a searing story of saintliness among macaque monkeys, join an exploration into the human potential for change. One of history's greatest monsters is transformed into one of its shining lights.
2020 • Astronomy
In what kind of world can a child born in 2020 expect to grow up? When did our slide into planetwide environmental destruction begin? Enter the possible world that awaits a 2020 baby in her twenties: one darkened by our refusal to confront the real and mounting challenges we face but one which still offers a message of hope.
2020 • Astronomy
Now that we’ve finished our tour of the planets, we’re headed back to the asteroid belt. Asteroids are chunks of rock, metal, or both that were once part of smallish planets but were destroyed after collisions. Most orbit the Sun between Mars and Jupiter, but some get near the Earth. The biggest, Ceres is far smaller than the Moon but still big enough to be round and have undergone differentiation.
Today Phil explains that YES, there are other planets out there and astonomers have a lot of methods for detecting them. Nearly 2000 have been found so far. The most successful method is using transits, where a planet physically passes in front of its parent star, producing a measurable dip in the star’s light. Another is to measuring the Doppler shift in a star’s light due to reflexive motion as the planet orbits. Exoplanets appear to orbit nearly every kind of star, and we’ve even found planets that are the same size as Earth. We think there may be many billions of Earth-like planets in our galaxy.
Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in smaller groups and larger clusters. Our Milky Way is part of the Local Group, and will one day collide with the Andromeda galaxy. Clusters of galaxies also clump together to form superclusters, the largest structures in the Universe. In total, there are hundreds of billions of galaxies in the Universe.